A feasible process for recycling valuable metals from LiNi_0.5Co_0.2Mn_0.3O₂ cathode materials of spent Li-ion batteries

ABSTRACT

The recycling of cathode materials for spent NCM has always been a major concern for the energy industry. However, among the current processing methods, the general leaching efficiency of Li is between 85% and 93%, with much room for improvement. The recovery of Ni, Co and Mn requires a high cost of secondary purification. In this study, to recycle the NCM cathode material, a route of sulphated reduction roasting – selective Li water leaching – efficiency acid leaching of Ni, Co, Mn – extraction separation – crystallisation was adopted. The results showed that after roasting (a temperature of 800 °C, a reaction time of 90 min, a carbon content of 26%, and a sulphuric acid addition of n_H2SO4:n_Li= 0.85), Li water leaching efficiency was 98.6%, followed by acid leaching of Ni, Co and Mn at around 99%. Mn, Co were extracted with Di-(2-ethylhexyl) phosphoric acid and 2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester respectively to obtain Ni, Co, Mn solutions, which eventually were crystallized for manganese sulphate, cobalt sulphate, lithium carbonate and nickel sulphate products, with high purity of 99.40%, 98.95%, 99.10%, and 99.95%. The results of this study improved the leaching efficiency of Li and were closely linked to the actual industrial preparation of Ni, Co and Mn sulphates, providing a feasible and promising basis for spent NCM cathode materials industrial recovery.

GRAPHICAL ABSTRACT

KEYWORDS:

• Li-ion batteries
• selective leaching
• extraction separation
• crystallization

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study, but feel free to contact the corresponding author at [email protected] to get them.

Additional information

Funding

We gratefully acknowledge support from the Inter-university Cooperation Project of General Undergraduate Colleges and Universities in Liaoning Province. And this work is funded by Doctoral Initiating Project of Liaoning Province Foundation for Natural Sciences, China (No. 2022-BS-334).